Determination of uranium is very important for effective use of seawater. Uranium is the most stable of all the elements in the ocean. The concentration and pH of uranium in the seawater differ a little according to the region and the depth, but the averages are 3.3×10-6g/L and 8, respectively.
Yun Chol Hun, a researcher at the Institute of Analysis, has reported a new combined method for the determination of trace uranium in seawater.
First, he added ferric chloride to 1L of seawater sample and adjusted the pH to 4. Then, he placed the solution at 80℃ for 30 min to coprecipitate uranium with iron hydroxide. After that, he dissolved the precipitate in nitric acid and electrodeposited it in EMIMBF4 to determine uranium by ICP-OES.
He evaluated the coefficient of diffusion (D) of electrodeposition of U(VI) on platinum electrode in EMIMBF, which was 3.31×10−9cm2/s. The electrochemistry experiments indicated that the reduction of U(VI) at platinum electrode in EMIMBF4 was a quasi-reversible single step two-electron transfer. The percent of chemical coprecipitation recovery of U(VI) was 98.9% and the recovery in electrodeposition was 99.5%.
For more information, please refer to his paper “Determination of uranium in seawater using chemical coprecipitation-ionic liquid electrodeposition by ICP-OES” in “Journal of Radioanalytical and Nuclear Chemistry” (SCI).